Where: f friction coefficient, for PTFE seal ring, f=0.5, the friction torque of the valve stem in the packing depends on the sealing form and working pressure. When pressed, the upper and lower seal rings bear uniform pressure, and the friction in the packing does not depend on the rotation angle of the ball. Therefore, the friction torque of the packing is as follows: where: df valve stem diameter; H1 Contact height between single ring packing and valve rod; The friction torque of Z1 packing ring number valve stem head can be expressed in the following formula: where: the calculated diameters of dF and dFT valve stem heads can be seen from the above, and the opening and closing torque of pneumatic ball valves is determined by many aspects. For pneumatic ball valves with a diameter of 100mm and a pressure within 1.6MPa, the opening and closing torque cannot exceed 60N-M. From the above analysis, it can be seen that the floating pneumatic ball valve has its limitations. Due to structural reasons, the torque will increase exponentially under large diameter and high pressure. Therefore, it is necessary to select the pneumatic ball valve with fixed structure, and we will further explore its applicability.

Nonmetallic compensator (fabric compensator, fiber fabric compensator)
Usage: Fabric compensator (fiber fabric compensator) can compensate axial and angular directions, and has the characteristics of no thrust, simplified support design, corrosion resistance, high temperature resistance, noise elimination and shock absorption. It is especially suitable for hot air pipes and soot pipes.
Connection mode:
① Flange connection type
② Receiving connection
Fabric compensator (fabric compensator) type:
① Compound form
② Angular type
③ Use of square non-metallic compensator
It is widely used in iron and steel plants, smelters, petrochemical plants, thermal power plants, cement plants, atomic power plants and other equipment such as flue gas desulfurization, dust removal equipment, air heating, flow assisted blowing and other equipment at the entrance and exit. It is much better than the metal expansion joint, so it is deeply criticized by users and vigorously promoted.